Final Cut Pro Studio - 5.1 & Stero DVD creation

Hi
I have a final cut pro project for a live band video, I have 5.1 audio supplied direct from the sound deck currently on channels 1-6, plus audience audio from the camera on tracks 7-8.
Usually I would export as a self contained movie, import that video into compressor using the DVD best quality settings, then take that into DVD studio pro.
The client is asking for the DVD to have a menu with the option of playing the videos in 5.1 and stereo, and I'm completely lost on the workflow, I've done some searches on google and still unsure, can anyone help please, apologies if I'm asking a lot but step by step would be hugely appreciated.

basically, you duplicate your final sequence,
set up one as 5.1, one as stereo, and export accordingly.

for 5.1, i have exported as individual tracks (one of the export options)
then assigned them in compressor.
there it suspect a way to set up and export 5.1 from an FCP timeline, but i've never done it.